JPH024684Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to a cuffed endotracheal tube. More specifically, the present invention relates to a cuffed endotracheal tube having a cuff configured to suppress an increase in internal pressure of the cuff due to diffusion of laughing gas into the cuff during general anesthesia.

(Prior art) In general, cuffed endotracheal tubes and cuffed tracheostomy tubes are used to prevent the leakage of anesthetic gas, oxygen, or air to the outside during general anesthesia or artificial respiration of patients with a tracheostomy, and to prevent the leakage of anesthetic gas, oxygen, or air into the esophagus. It is used to prevent accidental ingestion of vomit into the trachea, and is a cuff installed on the outer wall of the endotracheal tube or tracheostomy tube.

As is well known, an endotracheal tube is a tube that is introduced into the trachea from the oral cavity, and a tracheostomy tube is a tube that is introduced into the trachea through an incision in the tracheal wall without passing through the oral cavity. In any of these tubes, the gap between the tracheal wall and the tube is sealed by inflation of the cuff to isolate the lungs from the outside air. The present invention relates to the structure of a cuff commonly used in these endotracheal tubes, and in the present invention, the above-mentioned endotracheal tube and tracheostomy tube are collectively referred to as an endotracheal insertion tube.

The inner wall of the trachea is a mucous membrane containing countless minute capillaries, so if the contact pressure of the cuff to the inner wall of the trachea is too high, it will compress the capillary, stopping blood flow in the capillary and causing necrosis in the compressed area. may fall into. Furthermore, if this pressure is too low, not only will anesthetic gas, oxygen, or air leak, but vomit from the esophagus may flow into the lungs. Therefore, the contact pressure of the cuff against the inner wall of the trachea is not so high as to stop the blood flow in the capillaries of the trachea, nor is it so low that the gas delivered from the anesthesia machine to the lungs leaks, and that pressure state is maintained. It is hoped that

(Problems to be solved by the invention) General anesthesia is performed by intubating an endotracheal tube into the trachea, connecting it to an anesthesia machine, and delivering a mixed gas of oxygen and anesthetic gas to the patient from the anesthesia machine. This gas mixture is approximately 30-40% oxygen and laughing gas.
60 to 70%, and 0.2 to 2% of commonly used vaporized anesthetic gases such as frosene and etrene, which are characterized by a significantly higher partial pressure of laughing gas than the air inside the cuff, which does not contain any laughing gas. It is true. Therefore, the diffusion coefficient of laughing gas is significantly higher than that of other gases such as oxygen and nitrogen, which makes it easier for laughing gas to diffuse into the cuff, causing the cuff internal pressure to rise as anesthesia time progresses. As the anesthesia time progresses, the tracheal wall also becomes compressed with higher pressure.

The inventors of the present invention have arrived at the present invention as a result of intensive study on a cuff structure that suppresses the increase in the internal pressure of the cuff due to the diffusion of laughing gas.

(Means for Solving the Problems) That is, the present invention has a gradual expansion part on the outer wall of the endotracheal tube from the head side tube connection part to the trachea seal part, and from the trachea seal part to the lung side tube connection part. The cuffed endotracheal tube is characterized in that it is provided with a cuff having a non-progressively inflatable part that extends over the cap and has a surface area smaller than that of the progressively inflatable part.

FIG. 1 is a sectional view showing an example of a cuffed endotracheal tube according to the present invention, and the present invention will be explained below based on this. The insertion tube 1 is provided with an inflatable and deflated cuff 3 near its lung-side insertion end 2. The cuff 3 is airtightly connected to the insertion tube at the head side tube connection part 4 and the lung side tube connection part 5, and also communicates with an air inlet groove 6 provided in the surface layer of the insertion tube 1 from the head side. The cuff is inflated and deflated by a syringe or the like (not shown) communicating with the air inlet groove 6. As shown in FIG. 2, the endotracheal insertion tube is inserted into the trachea with the lung side insertion end 2 as the tip. After insertion, air is sent to the cuff 3 to inflate it and seal the gap with the trachea. At this time, attach the part of the cuff that seals the tracheal wall to the trachea sealing part 7.
shall be. The tracheal seal is the area where the cuff becomes inflated and has its largest diameter.

The cuff 3 of the endotracheal tube according to the present invention is
It has a gradual expansion part 8 extending from the head side tube binding part 4 to the tracheal seal part 7. Gradual expansion means that the expanded shape increases more slowly than in non-gradual expansion, which will be described later, and the surface area of that portion increases. Therefore, various shapes of the progressive expansion section can be used, examples of which are shown in FIGS. 3a to 3e. Particularly preferred are the shapes shown in FIG. 3 d and e. In FIG. 1, the portion from the lung-side tube binding portion 5 to the tracheal seal portion 7 constitutes a non-gradual expansion portion 9, which means that the shape of the expansion rapidly increases. In this invention, progressive and non-progressive are a matter of comparison;
It is important that there is a difference between the two.

By shaping the expansion portion as described above, the surface area of the non-gradual expansion portion 9 is made small and the surface area of the gradual expansion portion 8 is made large.

(Effect) Anesthesia using an endotracheal tube equipped with such a cuff will be explained. When anesthetic gas containing laughing gas is sent into the lungs through the insertion tube, the trachea is isolated from the outside world by the tracheal seal of the cuff, so the partial pressure of laughing gas increases on the lung side of the tracheal seal. Laughing gas permeates into the cuff through the membrane of the non-progressive inflation portion of the cuff. On the other hand, since the air on the head side, that is, on the outside world side, does not contain any laughing gas, the laughing gas in the cuff diffuses into the head side air through the membrane of the progressively inflated part of the cuff. If the permeation of this laughing gas into the cuff increases, unnecessary inflation of the cuff will occur, putting pressure on the tracheal mucosa. In order to prevent this, the lung-side surface of the cuff is made into a non-gradual inflation part, and its surface area is made small to minimize permeation into the cuff. Further, the surface of the cuff on the head side is made into a gradual expansion part to increase its surface area, to maximize the diffusion of laughing gas from inside the cuff to the outside world, and to prevent the laughing gas from staying inside the cuff. Such an idea has never been made before. For example, there is an endotracheal tube that has a cuff that is completely opposite in shape to that of the present invention. This endotracheal insertion tube appears to have a gently increasing cuff shape on the lung side in order to allow smooth insertion into the trachea without resistance.
With such a shape, it is impossible to achieve the purpose of the present invention, which is to suppress the increase in cuff internal pressure.

(Effects of the invention) The inventors conducted an in vitro test to confirm the effects of the endotracheal tube of the invention.

Laughing gas-containing anesthetic gas was supplied under the same conditions to an endotracheal tube with an inner diameter of 8.0 mm and a cuff according to the present invention, and an endotracheal tube with the same inner diameter and a cuff of the opposite shape than the present invention. The changes in pressure within the cuff were then measured. The results are shown in FIG. In Fig. 4, line A is an endotracheal tube having a cuff of the opposite shape to that of the present invention, and line B is an endotracheal tube according to the present invention, and the increase in the pressure inside the cuff is suppressed to an extremely low level by the present invention. can be seen.

Cuffs for cuffed tracheal tubes include low-volume, high-pressure cuffs and improved high-volume, low-pressure cuffs.
A low-capacity, high-pressure cuff has a small cuff capacity when inflated to equilibrium with atmospheric pressure, and further pressure is applied to inflate the cuff to seal the trachea. High-capacity, low-pressure cuffs have a large cuff capacity when inflated to equilibrium with atmospheric pressure, and the cuff reaches the tracheal wall with just this pressure, regardless of the shape of the patient's trachea, and then seals.
The trachea can be sealed simply by applying a pressure of 25 cmH ₂ O, and a low, even pressure is applied to the tracheal wall. High-volume, low-pressure cuffs and low-volume, high-pressure cuffs are used depending on the purpose, and the cuff shape of the present invention can be used in common with them.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing an example of a cuffed endotracheal tube according to the present invention, FIG. 2 is an explanatory view showing how the product of the present invention is used, and FIG. 3 is a cross-sectional view showing another example of the present invention. FIG. 4 is a graph showing the effects of the present invention. 1: Insertion tube, 2: Lung side introduction end, 3: Cuff, 4: Head side tube binding part, 5: Lung side tube binding part, 6: Air inlet groove, 7: Tracheal seal part,
8: Gradual expansion section, 9: Non-gradual expansion section.

Claims (1)

[Scope of utility model registration request] On the outer wall of the endotracheal tube, there is a gradual expansion section from the head side tube attachment section to the trachea seal section, and from the trachea seal section to the lung side tube attachment section, and the surface area is larger than the surface area of the gradual expansion section. 1. A cuffed endotracheal tube, characterized in that it is provided with a cuff having a non-gradual inflation portion with a small surface area.